As wireless networks evolve and grow in complexity, there are ongoing challenges associated with reaching targeted coverage levels. Recently, in an effort to boost coverage and enhance throughput in wireless networks, network operators have proposed deployment of wireless devices capable of transmitting at a maximum allowable transmit power that is higher than a current maximum allowable transmit power of off-the-shelf wireless devices and/or other currently deployed standard or low powered wireless devices.
As shown in Table 1 below, the maximum allowable transmit power for wireless devices can be defined by the power class of the wireless device.
TABLE 1Power Class 1Power Class 2Power Class 3Power Class 4Wireless Wireless Wireless Wireless Operat-DeviceDeviceDeviceDeviceingPowerTol.PowerTol.PowerTol.PowerTol.Band(dBm)(dB)(dBm)(dB)(dBm)(dB)(dBm)(dB)Band I31±226±223±221±2Band II——26±223±221±2Band III————23±221±2
For example, the maximum allowable transmit power level and tolerance (i.e., power error limits) with which wireless devices can transmit data on a given frequency band or sub-band (e.g., bands I-III) can be specified based on a pre-defined power class (e.g., power classes 1-4 illustrated in Table 1) of the wireless device rather than a physical maximum transmit capability of the wireless device. Off-the-shelf and/or other standard-powered (or low-powered) wireless devices are currently defined in LTE as power class 3 and/or power class 4 wireless devices. Power class 3 and/or power class 4 low-powered wireless devices can be configured with a maximum allowable transmit power level of +23 dBm for frequency bands I-III with a nominal power tolerance of ±2 dB (e.g., for E-UTRA bands). High-powered wireless devices are currently defined as power class 1 or power class 2 wireless devices. Power class 1 and/or power class 2 high-powered wireless devices can be configured with a maximum allowable transmit power level of +26 dBm for frequency bands I-II with a nominal power tolerance ±2 dB (e.g., for E-UTRA bands), as illustrated in Table 1.
Introducing additional high-powered wireless devices into a wireless network can negatively affect uplink system performance. For example, transmissions from standard-powered wireless devices (uplink transmissions) as well as signals received at the standard-powered wireless devices (downlink transmissions) may each be subject to interference caused by uplink transmissions from high-powered wireless devices operating in a high-powered transmission mode, particularly when both standard and high-powered wireless devices are operating on the same frequency band or sub-band.